1. Technical Field
The present disclosure relates to electrosurgical apparatuses, systems and methods. More particularly, the present disclosure is directed to electrosurgical systems utilizing return electrodes having multi-layers.
2. Background of Related Art
Energy-based tissue treatment is well known in the art. Various types of energy (e.g., electrical, ultrasonic, microwave, cryo, heat, laser, etc.) may be applied to tissue to achieve a desired surgical result. Electrosurgery typically involves application of high radio frequency electrical current to a surgical site to cut, ablate, coagulate or seal tissue. In monopolar electrosurgery, a source or active electrode delivers radio frequency energy from the electrosurgical generator to the tissue and a return electrode carries the current back to the generator. In monopolar electrosurgery, the source electrode is typically part of the surgical instrument held by the user and applied to the tissue to be treated. The patient return electrodes are typically in the form of pads adhesively adhered to the patient and are placed remotely from the active electrode to carry the current back to the generator.
The return electrodes usually have a large patient contact surface area to minimize heating at the tissue site. A larger contact surface area results in lower localized heat intensity. Return electrodes are typically sized based on assumptions of the maximum current utilized during a particular surgical procedure and the duty cycle (i.e. the percentage of time the generator is on).
The first types of return electrodes were in the form of large metal plates covered with conductive jelly. Later, adhesive electrodes were developed with a single metal foil covered with conductive jelly or conductive adhesive. However, one issue with these adhesive electrodes was that if a portion of the electrode peeled from the patient, the contact area of the electrode with the patient decreased, thereby increasing the current density at the adhered portion and, in turn, increasing the heating at the tissue. This risked burning the patient in the area under the adhered portion of the return electrode if the tissue was heated beyond the point where circulation of blood could cool the skin.
To address this problem various return electrodes and hardware circuits, generically called Return Electrode Contact Quality Monitors (RECQMs), were developed. Such systems relied on placing multiple electrodes on the patient during electrosurgical procedures in order to dissipate the heat.